The real estate mogul, who endorsed Romney on the eve of the Nevada caucuses earlier this month, is now touting the former Massachusetts governor on radio programs in those two key states. A loss in Michigan, which holds its primary on February 28, could cripple Romney, who was once considered a heavy favorite in the state where his father was governor.

Newt Gingrich and Rick Santorum are also aggressively competing in Ohio, which is perhaps the most critical of a number of states that vote on March 6.

Romney’s team asked Trump to help them by going on radio shows. And while Romney aides have not explicitly said this, Trump could appeal to the anti-establishment, Tea Party Republicans who have been hesitant to back the ex-governor. When Trump flirted with a presidential run last spring, polls showed him with strong ratings among the most conservative Republicans.

Trump, in an interview with Michigan’s WSGW on Monday, aggressively took on Santorum, who is leading some polls in Michigan.

“There is no gift, no Christmas gift that could be given better than Rick Santorum for the Democrats,” Trump said, according to NBC’s Matt Loffman. “They are just salivating at that. I don’t think they believe it’s going to happen, but boy would they like it to happen, because it would be an easy election.”

He added, “Mitt, by far, and this is very important, has the best chance of getting elected and beating Obama.”

Trump’s comments mirror those of Romney’s supporters and the ex-governor himself, largely highlighting Romney’s electability. It’s not clear if that message resonates with Tea Party Republicans, who have heard Romney allies make those arguments for months and still aren’t backing him.

Trump is now avoiding the controversial rhetoric he employed when he was considering his own presidential run, repeatedly questioning if President Obama was born in the United States.

His sharp rise in the polls back then suggested that his “birther” comments may have been at the heart of his appeal to Republicans.

Without that brash style, Trump sounds like the rest of the establishment politicians backing Romney, and that may do little to address the candidate’s problem with the most conservative members of his party.